The World Health Organization is investigating a cluster of possible polio cases in an eastern province of Syria.

If the cases are confirmed, they'd be the first ones in the war-torn nation in more than a decade. The country eliminated polio in 1999.

Syria used to have one of the highest polio vaccination rates in the region. If the virus has returned, it would be a high-profile example of the ramifications of the collapse of Syria's once-vaunted public health system.

Initial tests from the Syrian national laboratory in Damascus suggested that polio has crippled two children in the east, the WHO said Saturday. Further laboratory tests related to the cases are underway at the WHO's regional offices.

"We still need final confirmation from a laboratory, but all the indicators show that this is polio," Oliver Rosenbawer from the Global Polio Eradication Initiative toldThe Telegraph on Sunday.

The Syrian Ministry of Health says that it's treating the cases as part of a polio outbreak and beginning emergency vaccination campaigns in the area. The cluster of paralysis cases is in the eastern province of Deir Ezzor, which straddles the Euphrates River. That river flows east from Syria across Iraq.

Over the last two decades, the world has nearly eradicated polio. There were only 223 cases recorded globally in 2012, and they were all from remote areas of Nigeria, Afghanistan and Pakistan.

This year, there have been 296 cases worldwide, but more than half of them have been in Somalia, which had eliminated polio in 2007.

Before the civil war broke out in Syria in 2011, the WHO estimated that 83 percent of Syrian children were fully vaccinated against polio. By 2012 that vaccination rate had fallen to 52 percent.

The WHO has issued a regional polio surveillance alert in response to the cases from Syria. It is urging neighboring countries to launch supplementary polio vaccination campaigns to keep the virus from spreading.

In September, Israel underwent an emergency immunization drive after polio appeared in sewers around the country. The campaign aimed to give polio boosters to 1 million children under the age of 9.

But carrying out such vaccination campaigns in Syria amid the ongoing civil war, however, could prove very difficult.

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Transcript

AUDIE CORNISH, HOST:

The World Health Organization is gearing up to fight a potentially devastating polio outbreak in Syria. Almost two dozen possible cases are under investigation. And the WHO has issued a polio alert for Syria's neighbors. While WHO officials wait for confirmation that what they are dealing with is, in fact, polio, they're mass immunization to try to contain the outbreak.

NPR's Jason Beaubien reports.

JASON BEAUBIEN, BYLINE: Over the last two decades polio has been eradicated from most of the world except a few remaining hotspots. Health officials had thought that they were on the verge of wiping it out completely. If these cases of paralysis in Syria are confirmed as polio, this will mark the first time that the virus has emerged in Syria in 14 years.

DR. HAMID JAFARI: The government of Syria is responding to it like it is an outbreak of polio, and so are the countries immediately surrounding Syria.

BEAUBIEN: Dr. Hamid Jafari is the director for polio eradication operations and research with the World Health Organization in Geneva. He says the WHO is investigating a cluster of 22 paralysis cases among children in the Deer Ezzour Province in Eastern Syria.

JAFARI: Subsequently we've heard that there are two or three additional cases. So the information is still coming in. This area is a severely contested area so the information flow is not smooth and regular.

BEAUBIEN: Syria used to have one of the best polio immunization programs in the region. Prior to the start of the civil war two and a half years ago, 83 percent of Syrian kids were fully immunized against polio, according to the WHO. By last year that number had fallen to just 52 percent. Dr. Jafari says the WHO and the Syrian government are scrambling to launch emergency polio vaccination campaigns possibly as early as next week around the area where the suspected cases were found.

Additional immunization campaigns are being organized in neighboring Iraq, parts of Turkey, Lebanon, Jordan, the Palestinian territories, and even as far away as Egypt, these are all places that are currently considered polio-free.

JAFARI: In the initial response in these neighboring countries, these will be nationwide campaigns so that all people will be vaccinated, because the risk of spread is high.

BEAUBIEN: Carrying out those additional vaccination campaigns may be far easier outside of Syria than inside the country itself. There's been fierce fighting in the area where these cases were found. In addition, much of Syria's once vaunted health care system has collapsed.

TARA NEWELL: The conflict has affected the entire country and I don't think anyone is immune to it.

BEAUBIEN: Tara Newell, the head of mission for Doctors without Borders in Syria, says the health needs of Syrians are vast and the humanitarian response inside the country has been minimal.